The present invention relates to testing of tubes pipes and other hollows, particularly of pipes having thick walls and a large diameter.
A variety of methods are known for inspecting pipes, tubes, etc. for purposes of detecting any defects. One method that is commonly used employs X-rays and equipment for taking X-ray pictures. The German Pat. No. 1,939,933 discloses that an X-ray sensitive film be placed manually onto the pipe prior to moving the pipe into the test chamber in which the X-ray picture is being taken. After the pipe has left that chamber, the exposed film is manually removed. This procedure is time-consuming and may well interfere with the overall procedure which is carried out in sequence of particular steps. This is particularly true if the X-ray test is carried out on line with an ultrasonic testing procedure involving the same tube or pipe and operating on a highly automated basis. Moreover, the inaccuracies inherent in the manual placement necessitate utlization of large film strips just to increase the safety margin. Modern ultrasonic test equipment is frequently used as a preliminary inspection and locating technique to find flaws and defects in a welding seam. The X-ray test is then used to further identify the defect. It is necessary here to correlate the two techniques so as to restrict the X-raying to those locations in the seam for which the ultrasonic tests had indicated the possible presence of a defect.